* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
img {
  /* 去除掉图片默认的3px */
  display: block;
  width: 100%;
}
a {
  text-decoration: none;
  /* 让a标签的字体颜色 继承 */
  color: inherit;
}
ul {
  list-style: none;
}
input {
  border: none;
  outline: none;
}
.clearfix::after {
  content: "";
  display: block;
  height: 0;
  line-height: 0;
  visibility: hidden;
  clear: both;
}
